Conventionally, an image forming apparatus employs a process cartridge system in which process means acting on a drum and a drum are integrated into a cartridge, and this cartridge is dismountably mountable to the main assembly of the image forming apparatus.
In this process cartridge system, the maintenance of the image forming apparatus can be carried out by the user himself or herself without depending on the service person, the operability can be remarkably improved.
Therefore, this process cartridge system is widely used with image forming apparatuses.
Here, a process cartridge (JP 2001-337511, for example) and an image forming apparatus (JP 2001-337511, for example) including a clutch for switching the drive transmission to the developing roller during image formation between on-state (during image forming operation) and off-state (during non-image-forming operation) have been proposed.